1 files changed, 145 insertions, 0 deletions
diff --git a/examples/imx7_colibri_m4/demo_apps/sema4_demo/sema4_mutex.c b/examples/imx7_colibri_m4/demo_apps/sema4_demo/sema4_mutex.c
new file mode 100644
index 0000000..366f481
--- /dev/null
+++ b/examples/imx7_colibri_m4/demo_apps/sema4_demo/sema4_mutex.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2015, Freescale Semiconductor, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * o Redistributions of source code must retain the above copyright notice, this list
+ *   of conditions and the following disclaimer.
+ *
+ * o Redistributions in binary form must reproduce the above copyright notice, this
+ *   list of conditions and the following disclaimer in the documentation and/or
+ *   other materials provided with the distribution.
+ *
+ * o Neither the name of Freescale Semiconductor, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived from this
+ *   software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/****************************************************************************
+*
+* Comments:
+*   This file contains the functions which write and read the SPI memories
+*   using the ECSPI driver in interrupt mode.
+*
+****************************************************************************/
+
+#include "FreeRTOS.h"
+#include "semphr.h"
+#include "task.h"
+#include "board.h"
+#include "sema4_mutex.h"
+#include "sema4.h"
+#include "debug_console_imx.h"
+
+static SemaphoreHandle_t xSemaphore[16];
+static uint32_t recursiveDepth[16];
+static bool nvicInit;
+
+void SEMA4_Mutex_Init(uint32_t gate, bool reset)
+{
+    assert(gate < 16);
+    assert(!xSemaphore[gate]);
+
+    /* We use counting semaphore because the sequence of take/give could not
+     * be guarenteed. */
+    xSemaphore[gate] = xSemaphoreCreateCounting(1, 0);
+
+    /* Reset the gate when required */
+    if (reset)
+    {
+        SEMA4_ResetGate(BOARD_SEMA4_BASEADDR, gate);
+        SEMA4_ResetNotification(BOARD_SEMA4_BASEADDR, gate);
+    }
+
+    /* NVIC initialize */
+    if (!nvicInit)
+    {
+        NVIC_SetPriority(BOARD_SEMA4_IRQ_NUM, 3);
+        NVIC_EnableIRQ(BOARD_SEMA4_IRQ_NUM);
+        nvicInit = true;
+    }
+}
+
+void SEMA4_Mutex_Lock(uint32_t gate)
+{
+    bool locked = false;
+
+    assert(gate < 16);
+
+    /* If already locked by this processor, just add recursive depth */
+    if (SEMA4_GetLockProcessor(BOARD_SEMA4_BASEADDR, gate) == SEMA4_PROCESSOR_SELF)
+    {
+        recursiveDepth[gate]++;
+        return;
+    }
+
+    while (true)
+    {
+        /* Critical section with ISR */
+        taskDISABLE_INTERRUPTS();
+
+        /* Enable unlock interrupt of this gate */
+        SEMA4_SetIntCmd(BOARD_SEMA4_BASEADDR, SEMA4_GATE_STATUS_FLAG(gate), true);
+        if (SEMA4_TryLock(BOARD_SEMA4_BASEADDR, gate) == statusSema4Success)
+        {
+            recursiveDepth[gate]++;
+            /* Got the SEMA4, unlock interrupt is not needed any more */
+            SEMA4_SetIntCmd(BOARD_SEMA4_BASEADDR, SEMA4_GATE_STATUS_FLAG(gate), false);
+            locked = true;
+        }
+
+        taskENABLE_INTERRUPTS();
+
+        if (locked)
+            break;
+        else
+        {
+            PRINTF("\n\r...Lock pending, waiting for the other core unlock the gate\n\r");
+            /* Wait for unlock interrupt */
+            xSemaphoreTake(xSemaphore[gate], portMAX_DELAY);
+            /* Got the unlock event, indicating the interrupt was disabled in ISR */
+        }
+    }
+}
+
+void SEMA4_Mutex_Unlock(uint32_t gate)
+{
+    if ((--recursiveDepth[gate]) == 0)
+        SEMA4_Unlock(BOARD_SEMA4_BASEADDR, gate);
+}
+
+void BOARD_SEMA4_HANDLER()
+{
+    BaseType_t xHigherPriorityTaskWoken;
+    uint32_t i;
+    uint16_t flag;
+
+    for (i = 0; i < 16; i++)
+    {
+        flag = SEMA4_GATE_STATUS_FLAG(i);
+        if (xSemaphore[i] && SEMA4_GetIntEnabled(BOARD_SEMA4_BASEADDR, flag) &&
+            SEMA4_GetStatusFlag(BOARD_SEMA4_BASEADDR, flag))
+        {
+            /* Because the status cannot be cleared manually, we have to disable the gate's
+             * interrupt to avoid endlessly going into ISR */
+            SEMA4_SetIntCmd(BOARD_SEMA4_BASEADDR, flag, false);
+            xSemaphoreGiveFromISR(xSemaphore[i], &xHigherPriorityTaskWoken);
+        }
+    }
+}
+
+/*******************************************************************************
+ * EOF
+ ******************************************************************************/